1. Field of Invention
The present invention relates to the decoration of glass substrates with organically based pigment compositions that are free of ceramic enamels, particularly for use with automotive glass.
2. Description of Related Art
Decoration of laminated safety glass by conventional ceramic enamels is constrained by the minimum thickness needed to prevent warping of the decorated sheet during the firing process. Prior art methods not only required thicker glass panels to withstand the heat of firing an enamel color/pigment package, but the enamel based pigment composition had to be applied prior to a press-bend or other heating operation. For two reasons, then, it was possible to get a rippled or warped glass pane: (1) because the glass ceramic pigment layer was bent along with the (double) glass layers and (2) because the panels were thick enough to withstand enamel firing. Prior art decoration methods could not employ screen-printing to apply the glass ceramic enamel to an already bent glass, because screen printing requires a flat surface, and because the ceramic based enamel would require a heating operation to sinter and fuse the enamel which could further cause warping or shape distortion.